The upSET coding sequence has been deleted and replaced with sequence comprising a single attP site followed by a loxP cassette that contains the Disc\RFPDsRed2.3xP3 marker.
Homozygosity for upSETΔ.DsRed+ is lethal with low escape rate, the few escapers are sickly and unable to reproduce with wild-type mates.
upSETΔ.DsRed+ heterozygosity suppresses the variegating white eye color phenotype of In(1)wm4 mutants (resulting in a larger number of flies with a greater extent of normal red pigmentation).
upSETΔ.DsRed+ is rescued by upSETBioTAP
The lethality of upSETΔ.DsRed+ homozygous mutants can be rescued by combination with upSETBioTAP.